99 Tile Lunar Mosaic

 Moon  Comments Off on 99 Tile Lunar Mosaic
Feb 112017
 

Just shot this on the 10th February with my 1/4″ DMK camera and DSSR’s automatic mosaic module. Stacked in Avistack, stitched in ICE and post processed in Krita. Click to see the full size image.

Click for full size image

Below is the DSSR mosaic preview window that lets you monitor mosaic progress. The blue tiles were sky which DSSR automatically skipped to save time – total time taken was 45 minutes. The Moon is egg shaped here because I used a vertical overlap of 50% and a horizontal overlap of 30% to ensure a good stitch in ICE.

Click for full size image

 Posted by at 8:12 pm

Aligning Eclipses in DVS

 Moon, Tutorials  Comments Off on Aligning Eclipses in DVS
Oct 072015
 

I was asked to help out some users align their image sequences of the recent eclipse of the Moon and this is the result using DVS.

[vimeo 141665784]

The following is my idea of the best way to proceed.

1. Use DSSR to Guide (optional)

DSSR can guide on full disk Moons and this has the advantage of minimising the frame to frame drift which speeds up DVS alignment. To do this, zoom out the video screen until the Moon is small enough that you can select the whole disk as a guide target. Reducing the size of the guide target reduces DSSR’s cpu hit and makes guiding easier.

2. Set Similarity to 10

Similarity is used to eliminate false matches in cases like sunspot groups where multiple possible matches occur. For eclipses, there will only be one Moon per frame so the Similarity filter is redundant. Setting it at 10 turns it off.

3. Set Size Parameter to Exactly Match Moon Diameter

You need to make the anchor box the same size as the lunar disk. First set the Drift parameter to 1 to minimise the time taken to display the anchor box after you click. Then click on the centre of the disk and adjust the Size parameter until the anchor box is the same size as the disk.

eclipse

You can then adjust the Drift setting to suit your image set wobbliness or turn on the search full screen option.

4. Optimise Anchor Swap Setting

This is the KEY parameter for eclipses. It determines how often the current alignment target is swapped out for the current best match. The quickest way in the long term is to make a second set of images at a reduced scale. DVS processing time goes up roughly as the 4th power of image size. Using half size images will align 16 times faster and quarter size images will align 256 times faster.

This speed increase allows you to quickly run a series of alignments with different swap settings and see which best aligns the moon. I tried settings of 1, 5, 10, 20 and then with the parameter unchecked. Setting 5 gave the best results.

5. Produce Intermediate Image Set

The great thing about step 4 is that you now have a good rough alignment of your animation which you can apply to your original image set. Load the original set and then click the Data button on the alignment module. Select the best data file from step 4 and enter 2 for half sized images, 4 for quarter sized images, etc.

Now export your frames as an image sequence.

6. Final Alignment

Load the image set from step 5. You can use a smaller drift value because the Moon should be aligned to within a few pixels. This greatly speeds up processing time and you can then do any manual alignment tweaks, crop, add overlays and export as normal.

This may seem tedious but I found that a set of 328 images from Jim Fakatselis of Peppermill Skies Observatory took 2h30m to align from scratch. Producing the 5 runs in step 4 took a total of 25 minutes and the final alignment took only 36 minutes because it was already roughly aligned. The method above was 2.5 times faster and the results were optimised because of step 4.

7. Tricks and Tips

  1. Avoid overexposing the bright parts of the Moon. Burning out the surface to white means that DVS has no features to align on. You can see this at the start of the animation above where the burnt out limb causes alignment drift.
  2. Avoid abrupt changes to exposure settings. These cause DVS to jump which you can see about 2/3rds way thru the video above.
  3. As noted above, use DSSR to guide your scope during the eclipse. Even a rough guidance will dramatically improve DVS processing time.
  4. Use DTA to export a copy of your original images to DVS format. This will allow you to add clocks, date and time overlays to your animation in DVS.
  5. Turn off your camera’s auto orientation feature.

Finally, here is another of Jim’s eclipse sequences captured on a second scope. Note how the Moon moves about 2/3rds thru due to the overexposed limb.

[vimeo 141995085]

 

 Posted by at 8:52 am

New Version of MS ICE Mosaic Stitcher Released

 Moon, News, Tutorials  Comments Off on New Version of MS ICE Mosaic Stitcher Released
Feb 072015
 

Microsoft have just released an update to their Image Composite Editor (ICE). I gave it a quick try on my last set of lunar mosaic tiles and it looks like a much nicer package. In particular, the export to disk is now almost instantaneous. Download the 64bit version here.

ICE Screenshot

ICE Screenshot

 Posted by at 9:05 pm

Another Lunar Mosaic Tutorial

 Moon, Tutorials  Comments Off on Another Lunar Mosaic Tutorial
Feb 022015
 

This was shot with my 5.5″ mak – DMK21 – HEQ5 Pro combo.

20150129 cropped

Scaled down terminator detail.

20150129 full

Click on the image to see it full size.

The image was made up of 50 video files which were automatically captured by DSSR as shown in this speeded up time lapse video. The blue tiles are dark sky which DSSR skips to save time. The whole capture process only took 23 minutes.

[vimeo 118480741]

I then used AS2_Cull_Movies  by Andrew Cool of SkippySky to remove videos with only a sliver of Moon because these will crash the stacking process.

AviStack then processed the videos in batch mode and ICE was used to produce the final mosaic.

 Posted by at 1:21 pm

Mosaic Tutorial

 Moon, Tutorials  Comments Off on Mosaic Tutorial
Jan 102015
 

This tutorial shows how to use DFM and DSSR to automatically capture lunar (and solar) mosaics and how to process them into a final image.  I used a Nexstar 4SE OTA on a HEQ5 Pro with a DMK21 camera for this tutorial.

First off, set up your scope and mount and make sure that DSSR has the correct FOV values in its telescope settings page. Let your scope cool down to ambient and then focus using DFM. Then capture your mosaics using DSSR as shown in this speeded up video.

 

DSSR will generate a preview image for each mosaic like this one below.

M 20150103183125 X1 preview

The blue tiles were dark sky which DSSR automatically skipped but you can see some tiles which are totally black or just have a sliver of Moon on them. We need to remove these before the next processing stage or they will crash the stacking programme. You could do this manually but this is very time consuming, especially for very large numbers of videos.

Luckily, Andrew Cool of SkippySky has produced a great app called AS2_Cull_Movies which will do this for you. You tell it where your videos are stored and what percentage of each video should be above a certain brightness threshold. I used 20% and a brightness threshold of 5. The app then checks each video and moves any rejects into a separate folder (or optionally changes their file extension). You can then move onto the video processing stage.

I use AviStack to process my videos into very sharp images. First, load all the videos from your DSSR video folder and select one of them with prominent features like craters or mountains. Change your settings to Processing>All automatic (except post processing) and Update display>None. Adjust the wavelets and other settings to give the best and sharpest image and process that single video. Remove that video using the red cross and press the Batch Processing button. AviStack will then run through all your remaining videos and produce an image from each.

Finally, open Microsoft ICE and drag all your images onto it. ICE will then stitch your mosaic together and you can then export it to disk. A final edit in your image editor of choice (I use GIMP) will give you an image like below. Compare this image with the shimmering videos in the video above.

Click for full size mosaic.

Click for full size mosaic.

 Posted by at 2:37 pm

Mosaic Preview Finally Fixed

 Moon, Tutorials  Comments Off on Mosaic Preview Finally Fixed
Dec 302014
 

DSSR has a cool mosaic module that automatically captures videos for making lunar and solar mosaics. Part of this module is a mosaic preview image that shows the progress of the capture process. This was a bit hit and miss in older versions but I just tried out version 4.7 and I think I have finally got it.

Note that my mount is very roughly aligned so I set the mosaic size to 0.8×1.0 degrees to make sure I got the Moon. First up was a mosaic with the scope west of the pier. This took 22min with each video at 10sec and the mosaic started in the top right tile. The blue tiles are sky which DSSR automatically skips using the Exposures module.

M 20141229182748 X1 preview

Next up I did a meridian flip and tried again. Continue reading »

 Posted by at 1:56 pm

First Winter DSSR Lunar Mosaic

 Moon  Comments Off on First Winter DSSR Lunar Mosaic
Dec 072014
 

I have now dusted down my winter observatory and I did a quick test mosaic using DSSR. This comprised about 100x 10sec videos which my HEQ5 zipped thru in about 15 minutes. The videos were batch processed in AviStack 2 and merged in Microsoft ICE. Click on image for full size.

Click for full size image

 Posted by at 1:48 pm

Lunar Flypass with Canon A810

 CHDK AstroKam, Moon  Comments Off on Lunar Flypass with Canon A810
May 052013
 

This is a movie I made with my £50 Canon A810 hooked up to my Nexstar 4SE. Best viewed in full screen. Turn off HD by clicking on the HD symbol if you have a slow connection.

 Posted by at 8:33 am

Canon A810 Moon

 CHDK AstroKam, Moon  Comments Off on Canon A810 Moon
May 032013
 

I have been trying out my £50 Canon A810 camera for astro work. An early trial was to connect it to my Nexstar 4SE scope with a Skywatcher digiscoping bracket and the results were pretty good.

Here is a sample and you can see more of the image by clicking on it (give the large image time to load if you zoom right in).

Click for full size image

 Posted by at 12:21 pm